1. Field of the Invention
Capturing and delivering carbon dioxide formed by calcining a carbonate.
2. Description of Related Art
The US 48 State domestic oil production peaked in 1970. Increasing fuel consumption with declining oil production has required growing oil imports until recently. The USA imported $10.3 trillion of oil from 1940 through 2011 (in 2011 US dollars), causing a similar net loss to its International Investment Position. The Energy Information Agency (herein “EIA”) of the US Department of Energy (herein “DOE”) projects the current increase in US oil production to peak about 2019 (EIA 2013). Water floods, gas floods of air, nitrogen, carbon dioxide (herein “CO2”), lighter hydrocarbons (such as methane and propane), water alternating gas (herein “WAG”), steam, surfactants, and/or foam have variously been used to enhance oil recovery or production (herein “EOR”), depending on resource depth, type and production. (Citations are detailed in References and Bibliography below.)
CO2-EOR: Using carbon dioxide to enhance oil recovery or production (herein “CO2-EOR”) has been commercially proven for over four decades since 1972. Wallace et al. (2014) report 58 million metric tons/year (3.0 Bcfd) of CO2 use in 113 projects in the USA in 2012. Kuuskraa & Wallace (2014) report 136 US enhanced oil recovery projects (CO2-EOR) that were producing 300,000 bbl/day of oil. i.e. 4.0% of US 2013 domestic production of 7.4 million bbl/day. They project US CO2-EOR production to double by 2020 to 638,000 bbl/day. That would reduce the USA's 5.3 million bbl/day of oil imports by about 12%. Kuuskraa et al. (2011) screened 7,000 US oil fields to find about 2,000 oil fields that are economically suitable for CO2-EOR.
Kuuskraa et al. (2013) report that “Next Generation” CO2-EOR could provide at least 100 billion bbl (13 billion metric ton) in economically recoverable US oil resources including CO2-EOR recovery from residual oil zones (herein “ROZ”) with at $85/bbl oil, $40/metric ton CO2 (about $2/Mscf) and a 20% Internal Rate of Return (herein “IRR”) before tax. Such economic Next Generation CO2-EOR oil would nominally need 33 billion metric ton of CO2 of which 30 billion needs to come from industrial/power sources. Wallace (2014) reports about 135 billion barrels (19 billion metric tons) of economically and technically recoverable conventional US oil using “Next Generation” Enhanced Oil Recovery, including ROZ, Alaska and offshore Gulf of Mexico. Such CO2-EOR could use 45 billion metric ton (t or “tonne”) of CO2. Kuuskraa et al. (2013) project 1,297 billion bbl technical global CO2-EOR oil recovery potential.
CO2 Shortage: However only about 2.3 billion metric ton of CO2 are conventionally available for this Next Generation EOR from existing natural and anthroprogenic sources (7% of that needed for the US identified economic EOR oil potential). While CO2-EOR provides about 4.5% of US production, ARI (2010) identified: “The single largest barrier to expanding CO2 flooding today is the lack of substantial volumes of reliable and affordable CO2.” Kuuskraa et al. (2011) affirmed that: “ . . . the number one barrier to reaching higher levels of CO2-EOR production is lack of access to adequate supplies of affordable CO2.” Melzer (2012) observed: “Depletion of the source fields and/or size limitations of the pipelines are now constricting EOR growth . . . . The CO2 cost gap between industrial CO2 and the pure, natural CO2 remains a barrier.” Trentham (2012) observed “Accelerated ROZ deployment has clearly created unprecedented supply problems; many other unlisted projects await CO2 availability to begin implementation.” Godec (2014) states: “The main barrier to . . . CO2 EOR is insufficient supplies of affordable CO2” and that new industrial sources need to be developed to supply 17 of 19 billion metric tons of CO2 required to recover 66 billion bbl of conventional economically recoverable US CO2-EOR oil.
The Energy Information Agency (2014) projects that because of CO2 shortages, CO2-EOR will only increase to about 0.74 million barrels per day by 2040, enabling 5.2 billion bbl CO2-EOR oil for 2013-2040. Compare, about 1.5 billion bbl CO2-EOR oil produced from 1972 to 2012. The remaining 94% of identified economic CO2-EOR resources require developing major new industrial CO2 sources.
Cement CO2: With about 5% of global CO2 generation, the cement industry is nominally a potential source of industrial CO2. In EPA (2010), the Environmental Protection Agency reviews alternatives for reducing cement industry emissions. However, reviews of CO2 supplies for CO2-EOR do not mention current or planned CO2 sources from lime or cement production. The EIA expects that any development of CO2 from cement plants would take seventeen years from development to significant market penetration (seven years development followed by ten years for market acceptance). The EIA projects only 4% of Estimated Ultimate Recovery (EUR) of such CO2-EOR with CO2 from cement might be achieved.
Economic constraints: In mature calcining markets, such as for commodity lime and cement, economic downturns drop product demand causing strong declines in profitability often forcing operators to idle calciners. US cement production dropped 33% from 2007 to 2009 and a drop in price from $104 to $90 by 2011, causing plant closures and idled kilns. The EIA (2012) projected that capturing CO2 from cement plants, compressing it, and delivering it to an CO2-EOR project site via pipeline would cost more than twice that of conventional CO2 delivery from Natural Gas Processing ($4.29/Mscf vs $1.92/Mscf). Capturing CO2 from pulverized coal plants was projected to cost even more, while increasing electricity costs more than 30%.
Location & pipelines: Cement and lime kilns are almost always located close to or near to population centers or major industrial users. However, most oil fields are in geological basins distant from such population centers or industrial manufacturers. Conventional petroleum practice uses pipeline CO2 delivery as the lowest cost means to transport CO2 from natural or anthroprogenic sources to CO2-EOR oilfields. Conversely, the limestone or lime transport distance is minimized, as lime and limestone are more costly to transport than delivering CO2 by gas pipeline. While the US has some 805,000 km (500,000 miles) of natural gas pipelines, More than one billion dollars worth of natural gas was flared from the Bakken oil field in North Dakota in 2012—for lack of natural gas pipelines. Furthermore, the USA only has about 5,800 km (3,600 miles) of CO2 pipelines.
Industry analysts predict that expanding CO2-EOR would require building a major new CO2 pipeline infrastructure from anthroprogenic sources to CO2-EOR oil fields including mature oil fields, “brownfield” residual oil zones (herein “brownfield ROZ”) below the Main Pay Zone (“MPZ”) in conventional oil fields, and “greenfield” residual oil zones (herein “greenfield ROZ”) separate from conventional oil fields not having mobile oil readily accessible by conventional primary oil production. Not In My Backyard (NIMBY) and environmental litigation delay pipelines. The typical time for permitting and constructing CO2 pipelines would seriously delay CO2-EOR projects. Waiting for CO2 pipelines would cause lost development opportunities causing greater wealth loss from fuel imports.
Calciners and surface miners: Industry practice is to permanently install cement and lime calciners near large population centers or industrial markets with multi-decadal operating lives. Today's large rotary surface miners far exceed the production capacity of calciners. For example, a large surface miner with a capacity of 400 to 3,600 metric ton/hour, might only take 10 to 90 minutes to produce a day's worth of limestone for a 600 metric ton/day lime kiln. Surface miners are typically operated on mining projects or on very large limestone resources near railways or rivers to transport crushed rock to major markets sufficient to support their rapid production.
Public carriers: In Texas, public carriers seeking to pipeline carbon dioxide must now find and document third party customers before they can apply for eminent domain access. Conversely, parties seeking public carrier carbon dioxide for CO2-EOR usually must financially commit to a pipeline with a long wait for uncertain delivery dates. The DOE (2012) only expects fields having more than 20 million barrels of original oil in place (OOIP) to be practical for CO2-EOR. These chicken-egg barriers strongly reduce the Return On Investment (ROI) for CO2-EOR projects from cement plants and constrain the potential oil production by CO2-EOR.
Environmental barriers: Regulators are imposing increasingly stringent emissions limits. The Environmental Protection Agency's proposed rule for cement kiln emissions (EPA 2013) will require further expensive plant modifications. With overcapacity and low prices, the calcining industry is not expected to build new capacity to capture CO2. Reviews of CO2 capture technology note high costs, risks, and large energy requirements. Such poor economics and contrary markets raise major barriers against delivering CO2 for CO2-EOR from conventional calciners. In 2012, none of the DOE's CO2-EOR planned demonstration projects included carbon capture from lime kilns or cement plants.
Global Warming regulations: Lobbyists emphasizing projected dangers of catastrophic anthroprogenic global warming are pressuring politicians and environmental agencies towards global warming mitigation, carbon sequestration, and major reductions in carbon dioxide generation. For example, the Environmental Protection Agency is promulgating greenhouse gas emission regulations for current and future electric power plants (EPA 2012B, 2014) that strictly limit CO2 emissions of current and future coal-fired electricity power plants likely necessitating CO2 sequestration. Conventional calcining typically generates two orders of magnitude higher NOx production per unit of energy use than gas turbine power generation. The EPA's proposed stringent new rules on coal emissions and likely future NOx and calcining restrictions will likely substantially increase calcining plant capital and operating costs and delay issuance of plant permits. Calcining by oxicombustion is being studied.
Industry structure: Carbon dioxide is commonly assumed to be obtained as a commodity product at the lowest bid commanding only about 10% of the enhanced oil recovery margin. This provides little incentive to develop CO2 supplies. While hydrocarbon resources are drilled to prove hydrocarbon reserves, the quantity of limestone resources are commonly ignored.
Other Regulations: The Society of Petroleum Engineers et al. (SPE et al. 2011) provide guidelines for evaluating CO2-EOR reserves. However, the US Securities and Exchange regulations (SEC 2009) on declaring unconventional reserves normally permit declaring only those reserves that will be developed within five years at previously demonstrated development rates. The SEC further requires proof of enhanced reservoir response in the same reservoir or an analogous reservoir. However, it has commonly taken from two to ten years to prove reservoir response from the start of injecting CO2 for enhancing oil recovery (with an occasional demonstration in one year). The USA built the trans-continental railroad in six years (1683-1689), starting during a civil war. However, the US DOE now reports that the time from resource discovery to permit issuance alone takes seven to ten years. Such delays in permitting cause a “Catch 22” confounding regulatory problem: Common permitting and construction times to establish full scale CO2-EOR delivery projects needed to count reserves are longer than the SEC prescribed five years from the evidence of CO2 response required to demonstrate those reserves.